The present invention relates to a modular jack for data transmission for connecting a transmission line and a terminal equipment.
Conventionally, there has been provided a panel on a terminal equipment such as a personal comuter, facsimile machine and the like for connecting with a transmission line such as a private branch exchange, a circuit exchange and the like. The panel is used not only for connecting with the transmission line but also for diagnosing trouble both in the terminal equipment and the transmission line. Accordingly, the panel is provided with a U-link for disconnecting the terminal equipment from the transmission line and a switch for switching the connection of the terminal equipment to the transmission line or the loop test side, as well as being provided with a circuit connection terminal for connecting the terminal equipment with the transmission lines. Provided that the switch is switched to the loop test side, transmission lines associated with the terminal equipment are connected with receiving lines associated with the terminal equipment. This loop test is adopted for diagnosing trouble in the data transmission system according to CCITT advisory V 54. However, mounting the panel on the terminal equipment generates the problem that it is required to provide the U-link for diagnosing data transmission trouble, the manufactured panel must have a shape or a specification adapted to each terminal equipment depending on the number of transmission lines, namely, two transmission lines or four transmission lines. Accordingly, it is expensive to manufacture a panel as well as difficult to miniaturize the terminal equipment since the panel takes up space in the terminal equipment.